1. Field of the Invention
The present invention relates to a power window switch device and, in particular, to a malfunction detecting means which informs the driver of any malfunction in the opening and closing of the power windows.
2. Description of the Related Art
Presently, many automobiles are equipped with power windows which are opened and closed by the driving force of a motor. In an automobile equipped with power windows, all the windows can be opened and closed by operating a power window switch device provided at the driver's seat. Thus, even when the driver is alone in the automobile, he or she can open and close the rear seat windows without having to leave the driver's seat. Thus, compared to an automobile not equipped with power windows, an automobile so equipped is more convenient for to the driver.
On the other hand, in an automobile equipped with power windows, in which all the windows can be opened and closed with the power window switch device provided at the driver's seat, a danger exists that the windows at the rear seats will be closed unexpectedly and that a part of the body, clothing, etc., of a person sitting in a rear seat will be caught by the window.
There has been proposed a power window switch device which utilizes the fact that whenever a power window motor is blocked, the motor current rapidly increases. That is, the device detects an increase in motor current so as to detect a motor lock condition. It then emits an alarm sound to inform the driver of the occurrence of the malfunction.
However, the above conventional technique, which informs the driver of the occurrence of a malfunction through an alarm sound, has a problem in that it does not function as an alarm device for a driver who is hard of hearing. Furthermore, for a normal driver, the alarm sound is hard to hear when the environment is very noisy, so that it is difficult to quickly and reliably inform the driver of the occurrence of a malfunction.